The present invention relates to an arrangement and a method respectively for multiplexing and/or demultiplexing of channels in a digital communication system using time division multiplex with a switching arrangement providing for switching of data and multiplexing/demultiplexing of data in which control data and switching data are sent on connection links comprising logical interfaces from which resources can be requested.
The invention also relates to a switching arrangement comprising means for controlling multiplexing and/or demultiplexing of channels. Still further the invention relates to a communication system comprising such switching arrangement(s).
It is well known in synchronous communication systems to use arrangements for multiplexing and/or demultiplexing which means concentrating information on a number of communication channels on to one communication channel and deconcentrating information on one communication channel on to a plurality of communication channels respectively.
U.S. Pat. No. 4,630,261 shows a signal concentrator (multiplexer) comprising a buffer for storing messages and signalling information on a priority basis. In this arrangement signalling information is assigned the highest priority whereas generated voice packets are given a lower priority which in turn depends on whether the voice packets are newly generated or not. Furthermore low speed voice band data is given another priority and digital data packets still another priority. Entries in the buffer are contained in a look-up table indicating priority levels, identification, location in the buffer etc. Another table comprises the time recordings on when messages from a particular speech source exit the buffer. Via a controller running a priority algorithm the contents of the tables and the sequence entries from the buffer are used on a priority basis for forwarding to the communication channels. The entries having the highest priority are transmitted according to the first-in-first-out principle and they are then followed by the entries having lower priorities.
Via the priority algorithm is thus data shifted out on to a common communication channel.
WO 93/25031 relates to monitoring of the fill rate of an elastic buffer memory in a synchronous digital communication system. The object with the invention disclosed therein was to enable the monitoring of the fill rate of the channels using less hardware than in known systems. This is basically achieved by using a time division architecture for monitoring the fill rate so that the fill rate of two or more channels on the same hierarchical level is monitored on a time division basis in a monitoring unit which is common to the channels.
However, none of the cited documents discloses an arrangement for multiplexing and/or demultiplexing in a digital communication system which in an efficient way uses the resources on the channels. Furthermore it is difficult to connect transmission systems in such a way that the resources are efficiently used. Moreover only transmission systems for which the arrangements are particularly designed can be connected thereto.